Firework

Firework by Katy Perry has a mashup by Maximus Szczerbiak, and the song is also available in Just Dance Greatest Dances.

Appearance of the Dancer
The dancer is a woman with purple curly hair and if you look closely, she has pink earrings. She wears an indigo romper with a pink star and smaller pink circles, as well as an indigo wristband, a turquoise bow, and turquoise wedges.

Just Dance Greatest Dances
The background is an amusement park with fireworks (the song's namesake) and some bubbles,that comes from the center of the background and then goes out. Various colors, such as red, orange and pink appear, and the background is less blurry.

Mashup
The background is pink with falling stars, and they spin while they are falling.

Original
These are the dancers in Maximus Szczerbiak 's mashup.
 * Firework
 * Price Tag
 * Futebol Crazy
 * Forget You
 * Firework
 * TiK ToK
 * On The Floor
 * The Power [GM1]
 * Firework
 * Starships
 * Fame
 * We R Who We R
 * Iko Iko
 * Firework [GM2]
 * She Wolf (Falling to Pieces)
 * Firework [GM3]
 * Troublemaker
 * On The Floor
 * Firework [GM4]
 * Good Feeling
 * Firework

Just Dance Greatest Dances
This is mashup of the song available in the game and it is unlocked by collecting 30 stars in total.

Dancers

 * Firework
 * Proud Mary
 * Firework
 * Proud Mary
 * Satisfaction
 * Firework [GM1]
 * Walk Like an Egyptian
 * Body Movin' 
 * Firework [GM2]
 * Proud Mary
 * Firework
 * Proud Mary
 * Satisfaction
 * Firework [GM3]
 * Proud Mary
 * Firework [GM4]
 * Mashed Potato Time
 * Satisfaction
 * Firework [GM5]
 * Mashed Potato Time
 * Firework

Classic
There are 6 Gold Moves in this routine:

All Gold Moves: Point your right hand to the screen.

Original Mashup
There are 4 Gold Moves in the original mashup:

Gold Move 1: Slowly raise both of your arms, as if you were playing a saxophone. (The Power)

Gold Moves 2, 3, and 4: Point your right hand to the screen. (Firework)

Just Dance Greatest Dances Mashup
There are 5 Gold Moves in the mashup:

All Gold Moves: Point your right hand to the screen. (Firework)